C.3.3. PF: CHECK THE ITP OPPORTUNITY AND IDENTIFY REFERENCE AIRCRAFT
When PF entered the desired FL, the ATSAW function (refer to Figure C - 12):
- Checks that the ITP criteria are met as in C.2.6 – ITP Criteria
- Indicates if the ITP is possible or not (LSK 1R).
- Displays the aircraft in the ITP volume.
PF checks the ITP opportunity (possible or not and time) and identifies the Reference Aircraft in the ITP Traffic List (ITP distance, relative position, and flight number).
C.3.4. PNF: REQUEST THE ATC CLEARANCE
PF informs PNF that ITP is possible and indicates the Reference Aircraft (ITP distance, position, and flight number).
PNF requests an ITP clearance to ATC by CPDLC. PNF applies a specific phraseology in the CPDLC message. See notes below.

Figure C - 13: Enter desired FL in the CPDLC vertical request
It is recommended to edit the free text as follows (refer to Figure C - 15):
- 
LSK 1L: ITP

- 
LSK 2L: The ITP distance/relative position/flight number of the first Reference Aircraft

- 
LSK 3L: The ITP distance/relative position/flight number of the second Reference Aircraft (if any).

This method provides a clear view of entered data and permits the flight crew to rapidly check and/or correct one line.

Figure C - 16: Send the message from transfer the message to DCDU
DCDU The flight crew applies the usual procedures relative to CPDLC (e.g. cross-check, efficient management of DCDU). For more details on CPDLC, refer to Getting to Grips with FANS (see AIRBUS References).
Note 1: At the time of writing the brochure, the CRISTAL ITP consortium suggested an ITP phraseology to ICAO. ICAO evaluates the suggested ITP phraseology and should provide some recommendations. Figure C - 16 uses the suggested ITP phraseology. Note that the ITP Traffic list displays the information in the same sequence as in the suggested ITP phraseology (i.e. ITP distance/relative position/flight number, see Figure C - 12 and Figure C - 16).
Note 2: The CRISTAL ITP consortium(refer to C.5 – CRISTAL ITP) considers CPDLC as more efficient than HF voice to request an ITP clearance for the following reasons:
- 
CPDLC is faster than HF voice in terms of transmission time.

- 
CPDLC prevents errors that could occur with the poor transmission quality of HF voice, especially for the transmission of flight numbers.

- 
CPDLC is a Direct Controller-Pilot Communication (DCPC) media.

C.3.5. PF: PERFORM THE ITP
When the flight crew receives the ITP clearance (refer to Figure C - 17), PF must re-check that the ITP is still possible in the ITP TRAFFIC LIST page (refer to Figure C - 12). PF re-checks:
- Aircraft performances
- Green ITP POSSIBLE in the ITP TRAFFIC LIST page.
　
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